Mechanical time fuze for projectiles



July 18, 1967 F. H. RUHMANN MECHANICAL TIME FUZE FOR PROJECTILES 2 Sheets-Sheet '1 Filed Sept.

INVENTOR. FRANK H. RUHMANN a2 8% 7 J ATTORNEYS July 18, 1967 F. H. RUHMANN 3,331,325

MECHANICAL TIME FUZZ FOR PROJECTILES 2 Sheets-Sheet 2 INVENTOR. FRANK H. RUHMANN v United States Patent 3,331,325 MECHANICAL 'I'IME FUZE FOR PROJECTILES Frank H. Ruhmann, Southampton, Pa., assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 7, 1965, Ser. No. 485,650 4 Claims. (Cl. 102-83) ABSTRACT OF DISCLOSURE Internally adjustable fuze setting nose cone for projectiles in which the elements are maintained in coaxial relation to avoid eccentricity errors normally developed in setting devices of this type where a base ring and a conical cap thereon are graduated externally and are relatively rotatable for time setting. Time firing adjustment of internal elements is made through a central arbor extending axially through the cap with the outer end exposed'at the forward tip thereof and provided with a transverse slot for engagement and rotation by external means. The latter includes a cylindrical cap-like tool which seats on and fits the forward tip of the cap in coaxial relation thereto and is provided with a blade element adapted to engage the slotted end of the arbor to rotate it. An internal dial for time setting is observed through a window in the wall of the cap as it is moved by said central arbor in response to rotation and adjustment by said tool.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The present invention relates to mechanical time fuzes for projectiles such as artillery shells and the like, and more particularly to mechanical time fuzes of that type which are of cylindrical tapered shape adapted to screw into or fit into the forward end of such projectiles to form the tapered nose cone thereof.

The problem of setting fuzes accurately has existed since the beginning of mechanical time fuze development. Mechanical time fuzes are presently being set by turning the cap between the head and body of the fuze. The cap has time graduations on the outside which are aligned to a zero line on the body. This type of fuze is zeroed by aligning the cap and body zero lines and by locating the drop off point of the adjusting segment over the firing arm.

The design and present method of setting military artillery fuzes includes a multiplicity of areas where tolerances cause the cap and timing disc centers of turning to be cccentric. 'These eccentricities cause an angular displacement difference between the cap and the timing disc which is a setting error.

It'is therefore an object of the present invention to provide an improved mechanical time fuze of the type referred to wherein the zeroing and the setting of the fuze may be provided with a higher degree of accuracy than theretofor. With proper tolerances in critical areas the new fuze setting system has the capability of being set extremely accurately, and is of an improved and simplified construction to give lower manufacturing costs and reduced assembly difiiculties. Furthermore, many eccentricities involved in the setting operations are eliminated by fitting an internal setting dial directly to the fuze movement. The setting dial turns on the movement and it is zeroed directly to a timing disc element or segment by an eccentric pin. The fuze can then be zeroed easily and accurately. The outer cap is of one-piece construction with a minimum of internal parts. The setting system of the improved fuze is thus completely enclosed within the ice cap. The internal setting system has less mass and involves a lesser moment arm as compared with present fuzes and therefore the setting torque can be reduced.

The invention will further be understood from the following description when considered with reference to the accompanying drawings, and its scope is pointed out in the appended claims.

In the drawings,

FIG. 1 is a side view of a mechanical time fuze of the improved type embodying the invention and adapted to provide the forward nose cone of an artillery shell by attachment to the forward end thereof.

FIG. 2 is an enlarged View of the fuze shown in FIG. 1, taken on the section line 22 thereof, and shows details of the interior construction in accordance with the invention,

FIG. 3 is a side view, partly in section, of a setting wrench for attachment to and adjustment of the fuze shown in FIGS. 1 and 2 at the forward nose-cone tip thereof,

FIGS. 4 and 5 are plan and side views respectively, of an internal assembly of the fuze mechanism of FIG. 2 showing further details thereof,

FIG. 6 is an enlarged View, in perspective, showing the entire fuze setting system assembly,

FIG. 7 is a fragmentary view, in elevation, of a portion of the outer cap of the fuze showing the dial window and dial therein for setting in accordance with the invention, and

FIG. 8 is a further enlarged view of a portion of the assembly of FIG. 6, in plan view, showing further details of the setting adjustment thereof in accordance with the invention. 1

Referring to the drawings, wherein like parts throughout the various figures are designated by like reference symbols and referring particularly to FIGS. 1, 2 and 3, an outer conical tapered cap 10 provides a housing for the fuze setting mechanism 11, and is assembled with the fuze body 12 in which the movement assembly and timer 13 is mounted. A fuze cap socket wrench 14 seats on the forward end of the housing cap and engages a slot 15a in a setting arbor 15 by means of a screwdriver type blade 14a in the wrench, as is obvious from a view of the construction shown. The Wrench alone is used to set the fuze for time and thus provide a simplified externally applied element and positive control. It operates by turning the arbor 15 which is connected with a setting disk assembly 16 and turns the setting disk assembly to a proper position as viewed from outside the cap and casing of the shell. The latter assembly is held to the arbor by a buttonhead screw 17. The fuze body is provided with a cylindrical base or lower end 19 which is screw-threaded for joining to a projectile or shell.

The setting disk assembly includes a setting disk '18 with a setting pin 20 which engages and drives the timing disk assembly 21. The latter assembly determines the fuze firing time. An eccentric pin 22 is engaged in the slot of setting dial 23 for the purpose of zeroing the fuse. The hammer spring assembly operates to disengage the timing disk leaf 25 from the setting pin 20 during setback or firing. Hammer spring screws 28 or like means provide a mounting for the hammer spring 29 on the setting disk 18. A retaining ring 30 holds the eccentric pin 22 to the setting disk 18 and a set screw 31 locks the eccentric pin 22 in place.

The setting dial 23 provides graduations 32 for setting time into the fuze and is viewed through a window 33 in the cap end. The window glass or plastic cover plate 34 is retained by the metal window plate 35 which is held to the cap by any suitable means such as the screws indicated. The window structure may also be simplified by providing a circular window assembly which is forcefitted into a planed hole in the cap, instead of the milled opening shown. The cap itself is best manufactured by casting and final machining in a lathe.

A safety pin 36 located in the cap is provided to prevent the hammer spring assembly 24 from disengaging from the timing disk assembly 21 and the setting pin 20 while the fuze is set on safe. An arbor torque nut 37 threaded into a central counter-bore within the cap may be turned to apply setting torque to the setting arbor by applying increasing pressure to a cup-shaped or belleville spring 38. An arbor locking nut 39 similarly threaded within the counter-bore prevents the arbor 15 from shifting against the dial 23 during firing or setback. Both nuts are finally secured to the cap to prevent loosening as by the pins 40 indicated. The nuts 37 and 39 are assembled into the cap by suitable forked wrench means as is usual with externally threaded nuts of this type. A bearing washer 41, a spring washer 42 and a lock-nut washer 43 are used as slip washers to prevent wear in operation. However, the arbor 15 may be so formed that certain of these washers can be dispensed with. An O-ring seal 44 is used to seal the setting'arbor 15 at the forward end of the cap 10 as indicated in FIG. 2, and at the rear end of the cap a second O-ring 45 is provided at the end of fitted junction of the cap with the body 12, also as indicated in FIG. 2.

The movement assembly 13 is carried by and located on the body 12 by a body-locating pin 46 and by the body assembly screws 47. The cap 10 is located on the body 12 by a cap locating pin 49 which extends radially inwardly from the body. The body ring lock 50 locks the cap 10 to the body 12 by pressure from the four setscrews 51. A zero indicator 52, which mounts in the main spring housing 13, is viewed from the window 33 and is used as the zero point against which the dial 23 is set. The zero indicator 52 is made adjustable for the purpose of zeroing the fuze. A set screw 55 operating in an elongated slot 56 is provided for this purpose in the present example. A relatively thin circular safety disk 27 is mounted on the arbor axis below the timing disk 26. The safety disk 27 includes a segment 53 having a trailing edge 54 which prevents accidental firing of the fuze while set on the zero and safelpositions. It does so by the trailing edge 54 which keeps the firing arm 59 from plunging into the timing disk slot 63. The engraved line 60 on the segment 58 determines the position of the dial 23 which has a matching engraved line 61. These lines or marks are aligned during the zeroing of the fuze, by adjusting the eccentric pin 22. The hole 57 in the cap is closed and sealed after the eccentric pin 22 is adjusted therethrough when zeroing the fuze.

The timing disk segment 58 is welded to the timing disk 26 by spot welds 62 so that they both move together as one unit instead of being adjustable by eccentric screw or like means as in previous designs. It will further be noted that the external cap graduations normally used are replaced by the engraved setting dial which is internal and protected. Also the cap has a window for viewing the dial and the cap is not capable of turning with respect to the body as it is not made in two pieces as in present fuze designs. The fuze setting error is further reduced by having the timing disk assembly 21 and the setting dial 23 both driven by the setting disk 18. This eliminates differences in displacement between the two parts which might cause setting errors. The timing disk assembly 21 is moved for adjustment by means of the setting pin mounted in the setting disk 18 which engages the slotted timing disk leaf 25. The setting dial 23 is adjusted by the eccentric pin 22 (also mounted in the disk 18) which extends through a slot 63 (FIG. 6) in the inner flanged edge of the dial. By turning the eccentric pin 22 the setting dial 23 is zeroed to the timing disc segment 58 by means of lines 60 and 61.

In operation the fuze may be zeroed in certain steps for best results, as follows:

The fuze is assembled in two groupsone comprising the body 12 and the movement assembly 13 carried thereby and including the timing disk assembly 21 and the setting dial 23.

On the first group, turn the timing disk 26 until the timing disk segment 58 is somewhere in front of the firing arm 59.

Group 2 is the cap 10 and its internal assemblies which are placed over the body 12 and its internal assembly. The cap sub-assembly is located to the body sub-assembly by means of a slot 48 (FIG. 2) in the cap which fits over the pin 49 in the body. After assembly of the cap to the body, then turn the setting arbor 15 with the setting wrench applied to the end of the casing, as heretofore noted, to engage the end of the setting arbor with the screw driver point. Turn the arbor until the setting pin 20 is directly over the timing disk leaf 25, and then snap the assemblies together substantially as indicated in FIG. 2. Turn the wrench 14 until the drop off point is as indicated in FIG. 2. Turn the setting wrench 14 until the drop off point 66 of the timing disk segment 58 is aligned with the leading edge of the firing arm 59 as shown in FIG. 8. The latter is pivoted, at a point not shown, to move radially inwardly against the edge of the timing disk assembly 21. Check the crop off point firing arm relation by disassembling the cap from the body and inspecting the arrangement as shown also in FIG. 8.

If the alignment is satisfactory, place the setting dial 23 on the movement assembly and align mark 61 with the mark 60 on the timing disk segment. Next adjust the zero indicator 52 on the movement assembly to the zero on the setting dial 23 with a small screw driver. Now place the dial 23 in the cap 10 and engage its slot 63 with the eccentric adjustment pin 22.

Assemble the body 12 to the cap 10 again. The dial zero may not be aligned with zero indicator 52. The proper dial position must therefore be found by realigning the dial zero to the zero indicator. This is done by turning the eccentric pin 22 through the cap hole 57 with a small rod and locking the pin 22 in place with an Allen wrench. The window 33 and the window plate 35 should finally be assembled and sealed to the cap and the plug inserted in the eccentric pin access hole 57. The fuze assembly is then ready for use in the field by attachment to the end of the projectile or shell. In use, the arbor 15 is adjusted CW by the tool 14 to bring the dial scale, as viewed through the indicator window, and timing disk assembly to the proper time setting. The timing is initiated by the setback operation when the shell is fired.

As has been indicated heretofore, the hammer spring assembly 24 forming part of the setting disk assembly 16, as shown more fully in FIGS. 4 and 5, provides the hammers or inertial weights 27 on the hammer spring 29 which is secured to the setting disk assembly by mounting screws 28. This assembly is actuated in response to setback to drive the hammers downwardly against the timing disk leaf 25 and deforming it downwardly to disconnect it from the setting pin 20 carried by the setting disk assembly. The timing disk 26 is now free to run back CCW to the drop off point 66 of its connected segment 58. In other words, the timer in the movement assembly 13, through its shaft 64 and nut 65, then drives the previously set timing disk back to the firing arm 59 so that it may drop off when the drop off point 66 comes in line to clear it, as shown in FIG. 8. Note that the safety disk segment 53 turns with the timing disk, thus moving away from the firing arm 59 so that the firing arm will be released and free to drop off into the timing disk slot 63 when the disk is returned to its original position by the timer. This represents timed detonation of the fuze.

From the foregoing description it will be seen that a setting mechanism is carried by the cap 10 while the remainder of the timing mechanism, including the movement assembly and the timing disk assembly, is mounted on and carried by the body 12 whereby, upon joining the cap to the body, misalignment of parts and consequent eccentricity in operation as experienced in previous designs is greatly reduced and eifect an improved timing setting. This system thus reduces to a minimum, which have previously caused angular displacement difierences between the cap and body and resultant setting errors.

- This advantageous operation is brought about by having a setting dial which is mounted internally and turns on the axis of, and is zeroed directly to, the timing disk segment by an eccentric pin. This poses no difiiculty in the way of alignment because the eccentric pin has only to enter a slot.

This system represents a new approach to zeroing and setting fuzes with accuracy. It eliminates the upper and lower cap elements with the time graduations on the outside which were aligned to a zero line on the body. The two parts could thus turn relatively on different axes and out of alignment sufficient to cause undesirable setting errors. The present construction substantially eliminates this defect.

I claim:

1. A mechanical time fuze for projectiles comprising in combination, a cylindrical body adapted to be joined to the forward end of a cylindrical projectile as a part thereof and in coaxial relation thereto, a nose cone cap seated in fixed axial alignment with and on the body in prolongation thereof to provide the forward tip of said projectile, a coaxial timing movement assembly completely carried by the body, a setting mechanism carried by the cap and engaging the timing movement assembly, said setting mechanism including a setting disk assembly having a projecting setting pin, a movable annular dial element on said timing movement assembly detachably connected with and movable by said setting mechanism, a timing disk coaxially mounted on the timing movement assembly having a timing disk leaf and a timing disk segment projecting therefrom, said timing disk leaf being engaged by said setting pin, means carried by said setting disk assembly and including inertial elements responsive to inertial setback for moving and disconnecting said timing disk leaf from said setting pin and thereby releasing said timing movement assembly to permit timed firing operation of said fuze, a central rotatable setting arbor mounted in said cap, said arbor having an outer exposed forward adjustment end at the tip end of said cap for connection with an external rotary adjustment tool therefor and an inner end connected with said setting disk assembly to eifect rotation and setting thereof by said tool along with said dial element, means providing an observation window in the side of said cap in registration with a portion of said dial element, a zero indicator adjustable on said movement assembly to register with the Window and said portion of the dial element, and movable firing means held in a safe position by said safety disk segment, said firing means being releasable to fire said fuze in response to operation of said timing movement assembly to carry said safety disk segment past the firing point thereof as determined by the adjustment applied to the setting disk assembly through rotation of said arbor by said tool and read on the dial element through said window.

2. A mechanical time fuze for artillery shells and like projectiles comprising in combination, a cylindrical body adapted to be joined to the forward end of a projectile as a part thereof and in coaxial relation thereto, a nose cone ca-p seated in fixed axial alignment with and on the body in prolongation thereof and adapted to provide the forward tip of said projectile, a coaxial timing movement assembly completely carried by the body, a setting mechanism carried by the cap and including a setting disk assembly engaging the timing movement assembly through operating pin elements comprising a fixed setting pin and a rotary eccentric adjusting pin, a movable annular dial element coaxially mounted on said timing movement assembly and detachably connected with and movable by rotation of said eccentric pin, a timing disk coaxially mounted on the timing movement assembly and having a timing disk leaf projecting in one direction therefrom and a timing disk segment projecting in an opposite direction therefrom, said timing disk leaf having a releasable connection with said setting pin, means carried by said setting disk assembly and including elements responsive to inertial setback for disconnecting said timing disk leaf from said setting pin and thereby releasing said timing movement assembly to permit timed firing operation of said fuse, a central rotatable setting arbor mounted in said cap, said arbor having an outer exposed forward end adapted to be engaged and rotated by a tool element fitted and applied to the forward end of said cap, said arbor further being connected internally to said setting disk assembly and hammer spring assembly for rotation thereof to adjust and set the dial element and said timing disk assembly for operation at a predetermined time as indicated by said dial element, means providing an observation window in the side of said cap in registration with a portion of said dial, a zero indicator adjustable on said movement assembly to register with said portion of the dial, a firing element movable to a firing position and being held in a safe position by said safety disk segment, said firing element being releasable to move to said firing position in response to operation of said timing movement assembly to carry said disk segment past the firing point thereof as determined by the observed dial setting and rotation of said arbor by application of said tool element and the resultant setting of the timing disk assembly.

3. A mechanical time fuze for artillery shells and like projectiles comprising in combination, a cylindrical body adapted to be mounted on the forward end of a projectile as a portion thereof, a conical hollow cap seated on said body in fixed axial prolongation thereof and adapted to provide the forward tip of said projectile, a setting mechanism carried internally by said cap and provided With a longitudinally projecting setting pin and a longitudinally projecting eccentric rotary adjustment pin, a timing movement assembly mounted on and carried by said body within the cap and entirely free thereof in concentric relation to the axis of the fuze and projectile, a movable annular ring dial element carried by said timing movement assembly and engaged for movement by rotation of said adjustmg pm, means providing a scalable probe opening through said cap in alignment with said adjusting pin for effecting rotational adjustment thereof externally of said fuze, a rotary timing disk carried by said movement assembly and connected with said setting pin for movement therewith in response to operation of the setting mechanism in said cap, said setting mechanism including a central arbor extending axially through said cap with the outer end exposed at the forward tip thereof to provide an externallyoperable fuze adjusting element, said arbor having a transverse slot in the outer end and being thereby adapted for rotation and adjustment by external means, said lastnamed means including a cylindrical cap-like wrench adapted to seat on and fit the forward tip of said cap in coaxial relation thereto and having a transverse blade element for engaging the slot in the exposed end of said arbor to rotate it, an assembly carried coaxially by said setting mechanism in the cap adapted for disengaging the timing disk from the setting pin in response to setback there-by to initiate the timed firing operation of said fuze, a rotary safety disk in said movement assembly, means providing an observation Window in the side of said cap in registration with said dial element, movable firing means in said mechanism for initiating detonation of a charge in said projectile and maintained in a safety position in contact with said safety disk, and means for moving said disks by said movement assembly in operation, and said disks having cooperatively-related drop-out edges for unlocking and releasing said firing means at successive preset points determined by the dial setting observed through said window and applied through said central 7 arbor in response to rotation and adjustment by said wrench.

4. A mechanical time fuze as defined in claim 3, wherein a timing disk segment extending radially from said ti-ming disk and secured thereto is provided with an indicia mark and said annular ring dial element is marked with a similar indicia mark adapted to be adjusted in relation thereto for setting up said mechanism for operation, and wherein the dial element is further provided with an associated indicator means on the movement assembly, and the indicator means has a predetermined degree of adjustment with respect to the zero point of said dial element within the observation area of said window.

References Cited UNITED STATES PATENTS Varaud 102-84 Patton 10284 Fink 10271 Nabreski et a1. 102-84 Potts et a1. 10284 BENJAMIN A. BORCHELT, Primary Examiner.

10 G. H. GLANZMAN, Assistant Examiner. 

1. A MECHANICAL TIME FUZE FOR PROJECTILES COMPRISING IN COMBINATION, A CYLINDRICAL BODY ADAPTED TO BE JOINED TO THE FORWARD END OF A CYLINDRICAL PROJECTILE AS A PART THEREOF AND IN COAXIAL RELATION THERETO, A NOSE CONE CAP SEATED IN FIXED AXIAL ALIGNMENT WITH AND ON THE BODY IN PROLONGATION THEREOF TO PROVIDE THE FORWARD TIP OF SAID PROJECTILE, A COAXIAL TIMING MOVEMENT ASSEMBLY COMPLETELY CARRIED BY THE BODY, A SETTING MECHANISM CARRIED BY THE CAP AND ENGAGING THE TIMING MOVEMENT ASSEMBLY, SAID SETTING MECHANISM INCLUDING A SETTING DISK ASSEMBLY HAVING A PROJECTING SETTING PIN, A MOVABLE ANNULAR DIAL ELEMENT ON SAID TIMING MOVEMENT ASSEMBLY DETACHABLY CONNECTED WITH AND MOVABLE BY SAID SETTING MECHANISM, A TIMING DISK COAXIALLY MOUNTED ON THE TIMING MOVEMENT ASSEMBLY HAVING A TIMING DISK LEAF AND A TIMING DISK SEGMENT PROJECTING THEREFROM, SAID TIMING DISK LEAF BEING ENGAGED BY SAID SETTING PIN, MEANS CARRIED BY SAID SETTING DISK ASSEMBLY AND INCLUDING INERTIAL ELEMENTS RESPONSIVE TO INERTIAL SETBACK FOR MOVING AND DISCONNECTING SAID TIMING DISK LEAF FROM SAID SETTING PIN AND THEREBY RELEASING SAID TIMING MOVEMENT ASSEMBLY TO PERMIT TIMED FIRING OPERATION OF SAID FUZE, A CENTRAL ROTATABLE SETTING ARBOR MOUNTED IN SAID CAP, SAID ARBOR HAVING AN OUTER EXPOSED FORWARD ADJUSTMENT END AT THE TIP END OF SAID CAP FOR CONNECTION WITH AN EXTERNAL ROTARY ADJUSTMENT TOOL THEREFOR AND AN INNER END CONNECTED WITH SAID SETTING DISK ASSEMBLY TO EFFECT ROTATION AND SETTING THEREOF BY SAID TOOL ALONG WITH SAID DIAL ELEMENT, MEANS PROVIDING AN OBSERVATION WINDOW IN THE SIDE OF SAID CAP IN REGISTRATION WITH A PORTION OF SAID DIAL ELEMENT, A ZERO INDICATOR ADJUSTABLE ON SAID MOVEMENT ASSEMBLY TO REGISTER WITH THE WINDOW AND SAID PORTION OF THE DIAL ELEMENT, AND MOVABLE FIRING MEANS HELD IN A SAFE POSITION BY SAID SAFETY DISK SEGMENT, SAID FIRING MEANS BEING RELEASABLE TO FIRE SAID FUZE IN RESPONSE TO OPERATION OF SAID TIMING MOVEMENT ASSEMBLY TO CARRY SAID SAFETY DISK SEGMENT PAST THE FIRING POINT THEREOF AS DETERMINED BY THE ADJUSTMENT APPLIED TO THE SETTING DISK ASSEMBLY THROUGH ROTATION OF SAID ARBOR BY SAID TOOL AND READ ON THE DIAL ELEMENT THROUGH SAID WINDOW. 